(Reuters) - Wells Fargo & Co and its officials have racked up well over $4 billion (3 billion pounds) in penalties since a sales practices scandal erupted in 2016, and continues to face headwinds.Here are some of the remaining shoes that have yet to drop:Probes: A number of federal agencies are examining the bank and its employees for potential wrongdoing. The Department of Justice is looking into whether executives withheld details about fake accounts to the Wells Fargo board of directors and..